The invention relates to a disconnectable device for linking two closed volumes, such as a confinement enclosure and a transportation container, without breaking the confinement of said two volumes. Such a device is used in the nuclear industry, as well as in the chemical, medical, pharmaceutical and electronics industries.
Thus, in the nuclear and chemical industries the radioactive or dangerous nature of the products handled makes it necessary to confine these products in closed volumes to prevent any contamination of the external atmosphere. Conversely, in the pharmaceutical, medical and electronic industries, it is standard practice to have to work in a dustfree of sterile atmosphere. In this case, said atmosphere is also enclosed in a closed volume, so as to be protected against any contamination by the external atmosphere.
In all cases it is necessary to be able to have a means for introducing into and extracting from the closed volume products, devices and equipment of various types placed in another closed volume.
To this end, each of the closed volumes has at least one generally circular access opening defined by a flange and normally sealed by a door. The flanges and doors are provided with disconnectable fixing means making it possible to connect the flanges and doors of the two closed volumes. After opening the thus formed double door, the two closed volumes are linked and the transfers of products and equipment can take place.
In such a device, in order to permanently maintain the confinement of the closed volumes with respect to the external atmosphere, it is necessary to provide sealing joints, seals or gaskets of a particular type. Thus, any surface of the doors or flanges in contact with the outside atmosphere prior to engagement must necessarily be tightly separated from the closed volumes throughout the handling operations, i.e. both during engagement and when the double door is opened and introduced into one of the closed volumes. Conversely, the gaskets must also permanently ensure the confinement with respect to the external atmosphere of all surfaces of the flanges or plugs in contact with the internal atmosphere of the closed volumes when the doors are in place.
French Pat. No. 1 346 486 of the Commissariat a l'Energie Atomique describes a tight joining device between two tight enclosures, in which this result is obtained by using two joints having a curvilinear polygonal cross-section. These joints or gaskets are received in grooves having a square section and formed respectively in the door of one of the enclosures and in the flange of the other enclosure. When the enclosures are engaged and the double door is still in place, the desired confinement is obtained by a contact of the lips of the seals both with the groove in which they are received, with the door or flange of the corresponding closed volume and with the flange or door of the other closed volume.
Devices equipped with joints or seals of this type function in a satisfactory manner and in particular correctly ensure the desired confinement under normal usage conditions.
However, the use of lip seals, joints or gaskets is not completely satisfactory when significant pressure differences exist between the closed volumes and the external atmosphere. Thus, depending on whether the pressure within the closed volumes is below or above outside pressure, the lips of the seals must be differently oriented, which makes it necessary to use different seals in both cases. Moreover, in the hypothesis that the pressure gradient is provisionally reversed, there is a risk of the sealing quality suffering deterioration. Moreover, the manufacture of the lip seals described in French Pat. No. 1 346 486 requires special care, so that the costs thereof are increased.
The present invention relates to a disconnectable device making it possible to link two closed volumes without breaking the confinement thereof with respect to the external atmosphere, said device using gaskets of a novel type, which are simple and inexpensive and which can be used no matter whether the closed volumes are under an overpressure or underpressure with respect to the external atmosphere and which maintain the confinement even when they are subject to considerable pressure differences.